Absolutely and nearly nothing would need to be lit so a lot less energy. I also though about adding just the LCD matrix without the backlight in front of the mirror, would that work? I once had a clock that was transparent and had a display on it.

It’s very thin - especially without the bezel (I think it’s 13mm at its thickest) and the control board is completely detachable and only slightly bigger than the Raspberry Pi. It was a very easy install. Only downside is that the HDMI cable comes straight out - the back they all seem to these days. I solved this with a 90 degree HDMI cable.